package com.yang.design_principle.dry;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * @Description:
 * @Author: 杨 强
 * @CreateTime: 2022-10-13 10:57
 */
public class User {


    public static void main(String[] args) {
        Map<String, Integer> map = new HashMap<>();

        Integer yang = map.putIfAbsent("yang", 1);
        System.out.println(yang);

        Integer qiang = map.putIfAbsent("yang", 2);
        System.out.println(qiang);
    }

}
